INTERACTION

Ship to Ship Interaction

It is clear thus far that a great deal of caution needs to be shown when operating in narrow and shallow waters. It almost goes without saying, that extreme care is needed if it is now intended to bring another ship into the same situation by getting involved in an overtaking or passing situation as well.

Passing

In the interests of both simplicity and clarity, the sequence of events during a 'meeting end on' maneuver is contained in figures 1, 2, and 3.

Interaction.jpg
Interaction 1.jpg
Interaction 2.jpg

Overtaking

The overtaking operation is shown in figures 4, 5, and 6.

Interaction 4.jpg
Interaction 5.jpg
Interaction 6.jpg

The following general points should be noted.

  1. Prior to the manoeuvre, each ship remains in the centre of the channel for a long as possible. Failure to do so could expose either ship to bank effect, leading to a sheer across the path of the oncoming ship or grounding.

  2. Speed should be low to reduce the interactive forces. There is then, plenty of reserve power for corrective 'kicks ahead'.

  3. If the ships pass from deep to shallow water, at any time during the manoeuvre, the forces will increase drastically and extreme caution should be exercised.

  4. The smaller of two ships and tugs are likely to be the most seriously affected. Large ships should be aware of this and adjust their speed accordingly.

  5. Figures 1 to 6 illustrate the anticipated sheers that may develop throughout each manoeuvre and the maximum corrective helm that may be required, in this case, 35°.

  6. The engines should be brought to dead slow ahead for the manoeuvre, particularly turbine or fixed pitch propeller ships, so that power is instantly available to control the ship with 'kicks ahead'.

  7. On completion of the manoeuvre, each ship should regain the centre of the channel as quickly as possible to avoid any furtherance of bank effect.